//
// Created by Lenovo on 2020/10/11.
//
#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
using namespace std;
#define ll long long
const int maxn = 100000010;
int main()
{
    ll n;
    cin>>n;
    ll ans  = 0;
    for(int i = 1;i<=n;i++) ans += n/i;
    cout<<ans<<endl;
}